Africans had practiced slavery since ancient times. In most cases, the slaves had been captured in warfare and sold to Arab traders of northern Africa. Portugal and Spain became increasingly involved in the African slave trade during the early 1500's, after they had established colonies in the Americas. Portugal acquired African slaves to work on sugar plantations that its colonists developed in Brazil. Spain used slaves on its sugar plantations in the West Indies. During the early 1600's, the Netherlands, France, and England also began to use African slaves in the American colonies.

The Europeans obtained slaves from black Africans who continued to sell their war captives or trade them for rum, cloth, and other items, especially guns. The Africans needed the guns for use in their constant warfare with neighboring peoples. The slave trade took several triangular routes. Over one route, ships from Europe transported manufactured goods to the west coast of Africa. There, traders exchanged the goods for slaves. Next, the slaves were carried across the Atlantic Ocean to the West Indies and sold for huge profits. This part of the route was called the Middle Passage. The traders used much of their earnings to buy sugar, coffee, and tobacco in the West Indies. The ships then took these products to Europe.

On another triangular route, ships from the New England Colonies carry rum and other products to Africa, where they were exchanged for slaves. The ships then transported the slaves to the West Indies to be sold. The slave traders used some of their profits to buy sugar and molasses, which they took back to New England and sold to rum producers.

Slavery for profit. The slave trade was conducted for profit. The captains of slave ships therefore tried to deliver as many healthy slaves for as little cost as possible. Some captains used a system called loose packing to deliver slaves. Under that system, captains transported fewer slaves than their ships could carry in the hope of reducing sickness and death among them. Other captains preferred tight packing. They believed that many blacks would die on the voyages anyway and so carried as many slaves as their ships could hold.

Most slave ship voyages across the Atlantic took several months. The slaves
were chained below deck all day and all night except for brief periods of exercise. Their crowded conditions led to the chief horrors of the Middle Passage--filth, stench, disease, and death.

The Atlantic slave trade operated from the 1500's to the mid-1800's. No one knows how many Africans were enslaved during this period. The most reliable estimates suggest about 10 million blacks. The rising European demand for sugar helped create fierce competition for slaves and for new sugar colonies. From the 1500's to the mid-1800's, the Europeans shipped about 12 million black slaves from Africa to the Western Hemisphere. Nearly 2 million of these slaves died on the way. About 65 percent of the slaves were brought to Brazil, Cuba, Jamaica, Saint Domingue (now Haiti), and other sugar colonies. Brazil alone received about 38 percent. North America got about 6 percent. Slavery in the American South became common during this time, but it existed in many other areas of the Colonies as well.

Laws in the European colonies of Latin America showed considerable concern for the welfare of slaves. These laws allowed slaves to marry, to seek relief from a cruel owner, and even to buy their freedom. Such laws were rarely enforced, however. Partly for this reason, slavery was as cruel in Latin America as it was, later, in the United States. But slaves in the United States generally ate better, lived longer, received better medical care, and had a more secure family life than those in most other countries.

The continual shipment of large numbers of Africans to Latin America gave
slaves there certain advantages over blacks brought to the United States. For example, African customs could be retained more easily in Latin America. Slaves in Brazil and the West Indies had less need to adjust to white culture than did blacks in the United States. Blacks greatly outnumbered whites in parts of Brazil and in most West Indies colonies, but the Southern United States had twice as many whites as blacks. The greater number of slaves than whites in those Latin-American areas also made slave revolts more common there than in the United States. The biggest slave revolt in history broke out in Saint Dominque (Haiti) in 1791. Nearly 500,000 slaves rebelled against their French owners and took over the country.